Are Current U.S. Nuclear Power Plants Grid Resilience Assets?

Abstract

-This paper examines the concept of Grid resilience in the context of the North American electricity supply system and the role existing (Generation II) light water-cooled nuclear power plants (NPPs) play in enabling and enhancing Grid resilience. (Because of similarities in technology and plant design, it is likely that most of the discussion in the paper is also relevant to Generation III and Generation III+ light water NPP designs. The applicability of the analysis to Canadian CANDU and Russian VVER technology has not been assessed.) The paper asks and answers three compound questions: (1) what is Grid resilience, and what is a resilient Grid? (2) what is a resilient nuclear power plant (rNPP), and what are the basic functional requirements of rNPPs? and in light of the answers to these questions, (3) are today's U.S. NPPs significant Grid resilience assets? The conclusion reached is that existing U.S. commercial NPPs are safe and efficient capacity, energy, and reliability assets and they have demonstrated some Grid resilience benefit during regional weather events. However, today's NPPs do not deliver the Grid resilience benefits nuclear power can and should provide the nation. The author argues that nuclear power's unique fuel security (an attribute that could allow NPPs to energize the Grid during extended periods in which fuel could not be delivered to other types of power plants) is a compelling reason to develop future rNPPs that would deliver strategic Grid resilience benefits in the face of evolving hazards and threats to the U.S. Grid.

Enhancing Electric Grid, Critical Infrastructure, and Societal Resilience with Resilient Nuclear Power Plants (rNPPs)

“…Reactive power is power that flows out of phase with real power in alternating-current (AC) systems, as required to establish and maintain various electromagnetic fields in generators, motors, and transformers and along transmission lines. Previous analyses of such situations 5,6 support the conclusion that while current U.S. NPPs are safe and reliable energy and capacity resources, the design, operational, and regulatory approaches adopted to achieve these safety and reliability objectives have resulted in plants that are intolerant of transmission load and off-site power anomalies. Indeed, today's NPPs are frequently among the first generating plants to shut down and the last plants to return to service in the wake of major Grid disruptions.…”

“…1 The foundation for synthesis of a practical working definition of Grid resilience is a more general definition of system resilience such as the following: System resilience is the ability of a system to withstand a change or a disruptive event by reducing the initial negative impacts (absorptive capability), by adapting itself to them (adaptive capability), and by recovering from them (restorative capability). 9 With this in mind, the author has proposed the following working definition of Grid resilience 6 : Electric Grid resilience is the system's ability to minimize interruptions of electricity flow to customers given a specific load prioritization hierarchy.…”

“…The impacts of failure to serve various loads are dependent on the nature of the loads (customer class, specific societal function associated with the load, etc.). 6,10 Reference 6 provides a detailed discussion of the concepts of generic system and Grid resilience.…”

“…Issues such as the basic definition of Grid resilience, how Grid resilience can be measured and estimated, the value of Grid resilience to society, how Grid resilience can be monetized, and how Grid resilience can be achieved and secured have recently attracted significant attention in the United States. [2][3][4] Previous papers by the author [5][6][7][8] have examined the nature of Grid resilience and the role today's commercial nuclear power plants (NPPs) play in enabling U.S. Grid resilience as well as defined the key attributes and functional requirements for a new type of NPP: a resilient nuclear power plant (rNPP) that would be "intentionally designed, sited, interfaced, and operated to enhance Grid resilience."…”

Variable and Assured Peak Electricity Production from Base-Load Light-Water Reactors with Heat Storage and Auxiliary Combustible Fuels

“…In recent years there has been increased concern about "black sky" events that would cause grid collapse. [80][81][82][83] Examples of such events include geomagnetic disturbances induced by solar coronal mass injections, electromagnetic pulse attacks, and cyberattacks. In each case there have been historical events that suggest the risks may be significant given society's dependence upon electricity and that a low-carbon future would increase dependence on electricity.…”